Furnace



July 21, 1925. 1,546,450

J. w. MEAKER FURNACE Filed March 26, 1924 llllif T" 7 g5 I! l' Atacna)PATENT OFFICE.

JOHN W'.a MEAKER, 0F EVANSTON, ILLINOIS.

FUBNACE.

Application villetl Inroh', 1924. Serial No. 701,962.

To all wlwfnyz't may oom-em.' Be it vknown th t I, JOHNW. MEAKER, a

citizen of the United States, residin at Evanston, lin the county ofCook and tate of Illinois, have invented certain new and vusefulImprovements in Furnaces, of which the followin is a specification.I

My invention relates to certain improvements in hot air furnaces and isconcernedmore particularly. with ,the construction of furnaces using aiuid, that is, oil or gas, as

.. a fuel.

The principal object of the invention isYV to provide an oil or gasburnin furnace, more particularly for a domestlc heating plant, whichwill be so constructed as to" utilize to the fullestl extent the heatdeveloped by the burner and which -will distribute the heated air to thespace or spaces to which it is destined as effectively as possirble andin 4the quantity required. These purposes are carrled out by a certainnovel construction of the furnace calculated to eiiect a maximum heatexchange as between the combustion gases and the circulating air;and,`preferably, through the employment of an automatically controlledblower or fan for producing a continuous circulation of air through thefurnace to the space to be heated and from such space back to thefurnace.

`The invention comprises other incidental features of improvement to behereinafter described and claimed. It is realized that some -of theseimproved features might'be employed in the coal burning furnace; and

that, although it is preferableto use all of the described features inIcombination, it is not essential to do so. It is, therefore, myintention to coverl the invention in its preferred embodiment as shownin the drawing appended hereto and also all modifications of such embodent as may come with'- in the scope of the appended claims.

In the drawing- Fig. 1 is a fragmentary vertical sectional view of afurnace and a purtenances thereto constructed in accor ance with myinvention.

Fig. 2 is a sectional plan on line 2-2 of Fig. 1, and

Fig. 3 is a sectional plan view, on a larger scale, on line 3-3of Fi 1.

Referring to the drawlng, the furnace is shown as consisting of anouter, upright, cylindrical casing 10 and an inner casing 11,

these casings providing an inner combustion space 12 and an-outer .airspace 13.

Leading from the air space 13 are one or more flues 14'for conveyingheated air to the apartment or apartments to be heated. 15

lis ajreturn air flue, the inlet end of which extends. to an opening inthe iiooring `16 above thefurnace,'this opening bein provided with agridor register 17. n the particular embodiment of the invention showninthe drawing, which* embodiment,

however, is subject to modication lin this respect without departurefrom'the invention, the air lis contlnuou'sly circulated from thefurnace tothe apartments to be heated through Hot 'air flues 1 4 andback to the furnace Ithrough return flue 15. The installation has nofresh air pipe from outside the house although such pipe may be pro'vided if desired.

Preferably a blower ('by 'which I intend any means for creating airpressure) 'ispro vided for forcing lair from` the return flue throughthe' furnace and hot air flues. In the drawing'I have 'shown for thispurpose a fan 18 located between the vertical leg 19' and the horizontalleg 20 of the return iiue 15, which fan'is driven by an electric motor21. The blower may be operated continuously but preferably its aetlon isintermittent vand is controlled thermostatically inaccordance with thetem rature of the apartment or apartments to is, the bloweris set inoperation when the room temperature falls to a certain point and is shutof when. the tem raturerises above a certain point. The controlling theoperation of the blower which, of course, will be adjustable to operateat any particular temperature for which it is set, is designated 22andmay be employed lalso for opening and closing the fur-- nace damper7 butas this `arrangement is common it has not been shown on the drawheated.That ermostat lfor loo ing. As the fan., when idle, with its motor,

tends to block or interfere with the flow of air through the return flueand into the fur'- nace, a by-pass 23 around the blower outfit isprovided having a damper 24 which is closed when the blower isinoperation and opened when the blower is out of operation. Preferablythis damperis autom-atically controlled by the thermostat 22 whichcontrols thel operation of the blower. rI he mechanism for energizingand deenergizing fan motor 21 and opening and closing damper 24 may beas follows: 25 is a motor of any suitable type for giving oscillatingmovements to a lever arm 251. Motor 25 is in circuit with battery 26 andthermostat 22. 27 is a cord or chain attached to arm 25"L and extendingover a -sheave 28 and attached at its lower end to of high temperatureis more restricted,`

necessarily, because of the character of the fuel, than in a coalburning furnace. In order that an oil flame, for example, may be usedeconomically the circulating a-.ir must be brought to the center ofthecoinbustioii space by ducts constructed so as to bring about as completeheat exchangeI as is possible.y This I accomplish by providing ahorizontal partition 3S across the air space 13, dividing` said spaceinto upper and lower chambers 39, 40 and by providing a plurality of airheating ducts 41, the opposite ends Y of which open into the air spaceon oppositesides ofl partition 38, and which project radially toward thecenter of the combustion space 12. This division of the air passagethrough the furnace ,into a plurality of ducts necessarily increases thefrictional resistance to the air flow as well as diminishing theeffective cross sectional area of the air passage making very desirablethe forced draft above described in order that the volume of air passedper unit of time should be sufficient for the maximum requirement. Theburner 42, which may be of any preferred type, is located belowsducts41, the inner portions of the Walls of which are preferably providedwith radiating studs 48 which project into or, ifv desired, all the wayacross the ducts and into the vcentral space between the ducts for thepurpose yof increasing the amount of heat transferred from the gases inthe combustion space to the air currents passing through the air heatingducts 41. These studs may either be cast integral with the ducts or theymay consist of threaded bolts, as shown in Fig. 3, which are screwedthrough threaded openings in the walls of the ducts. The capacity of thestuds for absorbing and giving out heat is increased by their threading.This expedient for increasing heat transference is of importanceinasmuch as the diminished cross sectional area, of the air passageway(aggregate cross sectional areas of ducts 41 in comparison with thecross sectional area of the air space 13) either increases the volume ofair passed or, when the blower operates, involves amore rapid movementof the air. Preferably the oil or' gas supply will be regulated also bythe thermostat 22. With this in view the supply pipe 44 is provided witha valve 45 the operating lever 4G of which is connected by chain 47 witharm 29. Chain 47 has a weight 48 at its lower end. Valve 45 is open atall times but is moved to a throttling position when the blower isstopped.

`There are certain other incidental features which are preferable andshould be mentioned: It sometimes happens that one room of a house ismore difficult to heat than another. hot air Hue leading to such room,designated 14a in the drawing, may be directly connected with one' oftheair heating ducts, designated 41, by a short pipe section 49.

Under some circumstances. it may be advisable to allow acertain amountof air in chamber 40 of air space 13 to pass directly to the upperchamber 39. To makethis pos-i 'sible partition 38 is perforated, asindicated at 50, and a damper 51 provided for controlling the air flowthrough these perfora tions.

For the purpose of humidifying the heated air, the partition 38 may beformedvto provide a well or pocket 52 which may be supplied with waterthrough pipe 53, the valve 54 of which may be set so as to provide atrickle of water just sufficient to take care of evaporation; or, as ispreferable, the end of pipe 53 may be provided with a ball valve 55suitably caged.

Operation: When the requirement for heat is considerable the fan 18 isin operation to draw air through register 17 and re. turn air duct 15and force the same into the lower chamber 40 of the air space 13l of thefurnace. The damper 24 in ley-pass is closed, that is, in the positionshown in Fig. `1. The air being unable to pass directly from chamber 40to chamber 39 (eX- cept as a certain amount may pass through theopenings 50 dependent upon the adjustment of damper 51) the air forcedfrom the return duct by the fan "is compelled to passl in dividedstreams through the air heating ducts 41 which are arranged so as toextend directly above the burner 42. For this reason the circulating airis very -effectively heated and with the greatest possible economy offuel. The heat exchange -is facilitated by the radiating studs 43. Whenthe temperature in the apartment to be heated rises to a certain pointfor which thermostat 22 is set, the thermostat closes the circuitthrough motor 25 and the lever 251 is rocked to the left (Fig. 1). Thiscauses circuit breaker 33 to break the circuit through the llVhen thisis the case the' ico iio

fan motor 21 and rocks damper 24 to an open position so that air in thereturn duct 15 may by-pass the blower outfit. At the same time, in thecase of an oil or gas burning furnace, the supply of fuel tothe burneris diminished by partial closing of valve 45. In the case of a coalburning furnace the furnace damper will ordinarily be moved throughoperation of the thermostatic mechanism to slow down the tire. When thetemperature falls below the minimum for which thermostat 22 is set toact, moto-r 25 is energized to move arm 26 to the right and weight 32brings abo-ut the closing of damper 24; and a movement of the lever 35of circuit breaker 33 which closes the fan motor circuit 34, whereuponthe fan is set in motion and the sup-ply of fuel to the burner isincreased.

I claim:

l. In a hot air furnace having an inner combustion space and an. outerair space, a fluid fuel burner in the combustionspace., a. plurality ofair heating ducts opening at their opposite ends into the air space andextending through the combustion space into proximity with the burner,and means fon producing a forced draft of air through said air heatingducts.

2. In a hot air furnace having an inner combustion space and an outerair space, a Huid fuel burner in the combusti-on space, a partitionextending across `said air space, a pluralityy of air heating ductsopening at their opposite ends into the air space on opposite sides ofsaid partition and extending through the combustion space into proximitywith the burner, and means for p-roducing a forced draft of air throughsaid air heating ducts.

3. In a hot air furnace having an inner combustion space and an outerair space, a partition extending across said air space, a plurality ofair heating ducts opening at their opposite ends into the air space onopposite sides of said partition and extending through the combustionspace toward the center thereof, and a blower for forcing air throughsaid chiots.

4L. In a hot air furnacehaving an inner combustion space and an outerair space, ai' fluid fuel burner in the combustion space, a plurality-of air heating ducts opening at their opposite ends into the air spaceand extending through the combustion space into proximity with theburner, the walls of said ducts being provided with radiating studsextending into the ducts and into the space in the combustion chamberwithin said ducts and means for producing a forced draft through saidair ducts.

5. In a hot air furnace having an inner combustion space and an outerair space, a partition extending across said air space, a plurality ofair heating ducts opening at 'their opposite ends into the air spaceon0pmeans for producing a forced draft of air` through said air heatingducts.

6@ In a hot air furnace having an inner combustion space and an outerair space, a partition extending across said air space, air heatingducts opening at opposite ends into said air space at opposite sides `ofsaid partition and extending convergingly into the combustion space, thewalls of which ducts are formed with radiating studs extending into saidducts and into the central combustion space between the same' and meansfor producing a forced draft through said ducts.

7. In a hot air furnace having a combustion space and an air space, hotair fines extending from the air space to the apartments to be heated, areturn flue leading to the air space, a blower in said flue, a bypassaround said blower, and mechanism wherebyT the by-pass is closed whenthe blower is put in operation and is open when the operation of theblower ceases.

8. In a hot air furnace having a combustion space and anair space, hotair fines extending Vfrom the air space tothe apartments to be heated, areturn flue leading to the air space, a blower in said flue, a bypassaround said blower, and: thermostatically actuated mechanism whereby thebypass is closed when the blower is put in operation and is open whenthe ope-ration of the b-lower ceases.

9. In a hot air furnace having an inner combustion. space and an'outerair space, hot air fiues leading from the air space, a return flueleading to said air space, a partition extending across the air space, aplurality of air heat-ing ducts opening at opposite ends into the airheating space on opposite sides of said partition and extending towardthe center ofthe combustion space, and means for forcing air from theair return flue into said air space.

10. In a hot air furnace, the combination of outer and inner verticallyarranged, cylindrical casings providing an inner combustion space and anouter air space, a horizontal partition across said air space, aplurality of air heating ducts which openinto said air space at theiropposite ends on opposite sides of said partition and extend radiallyinto the co-mbustion space, a plurality of hot air fines leading fromthe air spacev above said partition, a return air flue leading to theair space below said partition, and a blower in said return air flue.

11. In a hot air furnace, the combination A of outer and innervertically arranged, ey-

lindric-al casings providing an inner combustion space Vand an outer airspace, a horizontal partition across said air space, a plurality of airheating ducts which open into f said air space at their opposite ends onopposite sides of said partition and extend radially into the combustionspace, a plun rality of hot air fines leading from the air space abovesaid partition, a return air flue leading to the air space below saidpartition, a blower in sai-d flue, a by-pass around the blower, a damperin the by-pass, and a thermostatically actuated' mechanism whichoperates alternately to set the blower in operation and close the damperand to stop the blower and open the damper.

12. ln a hot air furnace, the combination of outer and inner verticallyarranged, cylindrical casings providing an inner combust-ion space andan outer air space, a horizontal partition across said air space, aplurality of air heating ducts which open into said air space attheiibopposite ends on opposite Sides ofv said partition and extendinmenso radially into the combustion space, a plurality of hot air luesleading from the air space above said partition, a return air flueleading to the air space below said partition, said ducts being providedWith radiatfuel burner and means through which air vto be heated andproducts of combustion from the burner are adapted to be passed, saidfurnace being formed so as to provide a plurality of separate ducts forone of said gases Which extend into the space through Which the othergas is passed, and means for producing a forced draft of the air to beheated through said furnace.

JUHN W. MEAKER.

